An OVP circuit includes a voltage boost circuit, for boosting an input voltage into an output voltage in need and providing the output voltage to a load, a voltage control module for controlling the voltage boost circuit to boost an input voltage into an output voltage in need and for providing the output voltage to the load, an overvoltage protection module for monitoring a voltage of a positive terminal of the load to enable or disable the voltage control module, and an overvoltage adjusting module for monitoring an operation voltage of the load to adjust the overvoltage. It effectively prevents from the abnormal operation attributed by over practical operation voltage or prevents components from damage attributed by tardy protection. The present invention also proposes an LED backlight driving circuit using the OVP circuit and an LCD having the LED backlight driving circuit.